<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">One solution, although it may not be the best, would be to create some sort of land/ocean mask with your resolution of data, then use the maskout function to color the land areas. In my example, I have a crude land mask with all ocean values as a negative number. Then do something like:<div><br></div><div>ga-> set gxout grfill </div><div>ga-> set ccolor 15</div><div>ga-> d maskout(type.2,type.2)</div><div>Where type is my mask in my second opened file.</div><div>Then plot your field.</div><div><br></div><div>Attached is the result with my data</div><div><br></div><div>Colleen</div><div><img height="559" width="745" apple-width="yes" apple-height="yes" src="cid:4CE3F4A9-F537-4006-B04A-1EA6D7B161F8"><br><div><div><div>On Mar 1, 2012, at 4:57 AM, <a href="mailto:Pascal.ACHIM@cea.fr">Pascal.ACHIM@cea.fr</a> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div lang="FR" link="blue" vlink="purple"><div class="WordSection1" style="page: WordSection1; "><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US">Hello,<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US">I want to overlay a concentration map (for example) on a base map (eg continents in gray). Is it possible to do this with Grads? I tried with Basemap.gs, but it does not work, continents mask the concentration map. Attached is an example of what I want to do (the continents were colorized in gray after with Gimp).<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US"><o:p> </o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US">Thank you for your help!<o:p></o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US"><o:p> </o:p></span></div><div style="margin-top: 0cm; margin-right: 0cm; margin-left: 0cm; margin-bottom: 0.0001pt; font-size: 11pt; font-family: Calibri, sans-serif; "><span lang="EN-US">Pascal<o:p></o:p></span></div><span><FIGURE_03.png></span><span><ATT00001.txt></span></div></div></blockquote></div><br></div></div></body></html>